body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
    sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
*{
  margin: 0 ;
  padding: 0;
}
code {
  font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New",
    monospace;
}
.header{
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 50px;
  line-height: 50px;
  background-color: rgba(0,0,0,1);
}
.header ul{
  
}
.header>ul>li{
  list-style: none;
  float: left;
}
.header>ul>li>a{
  padding: 0 15px;
  color: #fff;
}
.layout{
  padding-top: 50px;
}